Some motorcycle designs involve the use of engines that are supplied with a lubricant (e.g., oil) stored in a tank that is physically separated from the engine. In some designs, these tanks hang from the motorcycle frame and involve the use of two oil pumps. One pump sends oil from the tank via a first oil line to the engine, whereupon the oil ultimately works its way to the bottom of the engine. The other pump sends the oil from the bottom of the engine back to the oil tank via a second oil line.
These tanks that hang from the motorcycle frame frequently detract from the appearance of the motorcycle. Moreover, they often place a static load on the motorcycle frame.